Mathematical Model of Heat and Moisture Transfer for Predicting Durability of Building Element

为了预测建筑构件的水分变化，讨论了0℃以上区域热湿传递的数学模型。在方程中，边界条件考虑了降水和气压。在此基础上，讨论并推导了冻结条件下热湿传递的控制方程。在那个方程式中，即使在摄氏零度以下也假定存在液态水。所得方程不仅在冻融区有效，而且在非冻融区有效。利用这些方程，对冻融条件下ALC试件的试验结果进行了分析。固体水（冰）含量和温度分布的计算结果与实验结果吻合较好。下一阶段，我们将尝试在方程中引入化学反应项。另一方面，我们试图分析由于含水量变化和分布导致的建筑构件变形。在吸湿区，应用上述控制方程对日本大阪木墙和螺柱在瞬态自然条件下的膨胀收缩进行了数值分析。得到了木墙各构件的变形顺序。在分析中，考虑了非各向同性。此外，还进行了螺柱在压缩条件下的变形试验。压缩效果没有清晰显示。

For the purpose of prediction of moisture variation in building elements, mathematical model of heat and moisture transfer are discussed in the region above 0 degree centigrade. In the equations, waterprecipitation and air pressure are considered in the boundary conditions. Addition to results, governing equations of heat and moisture transfer under freezing are discussed and derived. In those equation, existence of liquid water even below 0 degree centigrade is assumed. Equations obtained are valid not only in freezing/thawing region but in non-freezing region. Using these equations, experimental results are analyzed of test specimen of ALC under freezing/thawing conditions. Calculated results of solid water (ice) contents and temperature distributions are reasonably agree with experimental results. In next stage, we will try to introduce chemical reactions term in the equations.On the other hand, we tried to analyze deformation of building elements due to moisture content variation and distribution. In hygroscopic region, expansion/shrinkage of wooden wall and studs are analyzed numerically under transient natural conditions at Osaka, Japan, applying governing equation mentioned above. We obtain order of deformation of each elements of wooden wall. In the analysis, non-isotropic properties are considered. Furthermore, experiments of deformation of stud under compressed conditions are perform. Compressed effects are not shown clearly.